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The complete private bike-fit loop
Measure your position, check movement with your phone, make one small reversible adjustment and re-check it after real rides. No account, no upload and no invented fit score.
Confirmed baseline
Knee at bottom of stroke · 31°
Product proof, not a promise
Every result keeps the measurement, confidence, source and next action together. OpenBikeFit does not hide uncertainty behind a green score or turn one camera frame into a diagnosis.
Synthetic product sample
Not your resultExplore the complete loop. Every state keeps the measurement, uncertainty, physical setup and next action together.
01 · Baseline
Two independent takes agree closely enough to freeze a usable starting condition.
One +3 mm saddle-height trial is small enough to mark and reverse.
The closed loop
The market is full of calculators that end at a number and camera apps that end at an angle. OpenBikeFit connects the measurement to the physical adjustment, the rides and the fresh re-check.
Start with body measurements and the exact bike that is in front of you — not a generic rider avatar.
Three saddle-height methods, explicit measurement datums and a range instead of a false single truth.
A side-on phone camera checks movement while the recording and pose result remain on your device.
The workflow checks framing, visibility, usable cycles and repeatability before surfacing a measurement.
Freeze the baseline, mark the hardware and make one small adjustment with a physical route back.
No mystery score. You see what changed, why it is being tried, the confidence and what would stop the trial.
Give the change two or three real rides, repeat the measurement and keep movement separate from comfort.
A result closes only after the expected hardware state and fresh repeated readings agree.
Choose the job, not a generic funnel
Start from your body and bike
Height, inseam, goal and mobility become cited ranges for saddle height, setback, bar drop, crank length and frame coordinates — then a private passport keeps each bike distinct.
Open calculator →
Frame · steady · pedal · auto-lock
Five live gates hold the side view, framing, stability, light and cadence before a countdown captures six new clean cycles and returns an exact accept or retry.
Open Capture Director →
New deep workflow · target → shortlist → mechanic → re-check
Compare 2–4 exact sizes against measured Bar X/Y, rank real stem and spacer combinations, freeze one build in your local bike history and close it with repeated installed coordinates plus a separate 2–3 ride decision.
Open Frame Transfer Studio →Fit Path Router · local only
Three short choices route you into the useful part of OpenBikeFit. Nothing is uploaded and red flags always stop the recommendation.
Privacy is product architecture
Pose processing runs in the browser. Fit records, bike passports and comparison history stay on this device until you export or delete them. There is no account, advertising tracker or mandatory cloud profile.
Read the exact data flow →
Safety is a hard stop
Sudden, severe, progressive or off-bike symptoms stop autonomous fitting. Complex hardware work routes to a qualified mechanic; persistent symptoms route to an appropriate health professional. The app does not diagnose.
Evidence, with the limits visible
The classic 109% inseam formula misses the 25–35° knee-angle reference window in many riders. OpenBikeFit therefore uses formulas as starting estimates, keeps the method visible and asks the camera to verify the moving position.
A review screening 16,578 records found the strongest scientific agreement around saddle height. Other recommendations are labelled by confidence and separated from fitter convention rather than presented as law.
Audit every claim and source →saddle-height methods compared
independent takes when noise demands it
change at a time
medical or causal claims from a fit score
Straight answers
The practical questions riders ask before sharing measurements, trusting a range or deciding whether to involve a professional.
Yes. The calculator and camera measurement are free to use in your browser, with no account, trial or hidden fee. OpenBikeFit is maintained by Balance IT to make an evidence-led bike-fit starting point broadly accessible.
One that leaves your knee bent 25–35° at the bottom of the pedal stroke (the Holmes method). As a rough guide that is about 88.3% of your inseam measured from the bottom bracket to the top of the saddle — for an 84 cm inseam, around 742 mm. The calculator computes a range from your proportions, goal and flexibility.
A professional fit may be especially valuable for persistent pain, injury recovery, complex asymmetry and competitive racing. OpenBikeFit provides a free, evidence-led first pass: published reference ranges plus an on-device camera check. It cannot reproduce a fitter's physical assessment, and warning signs stop the recommendations.
From peer-reviewed literature: systematic reviews (Bini 2011, Husband 2024) and studies including Peveler 2008/2011, Martin & Spirduso 2001 and Holmes 1994. Every result separates evidence from fitter convention and links to the relevant source.
Your fit inputs, video and results are not uploaded: the pose engine runs on your device and fit records stay in your browser. The optional Help form is separate and sends only the feedback you deliberately submit. There is no account or ad tracking.
No. It is an educational tool, not a medical device. For pain that persists off the bike, wakes you at night, gets worse or follows an injury, OpenBikeFit stops autonomous recommendations and directs you to an appropriate professional.
Start with the bike you already own
Two body measurements, a cited range and a private route from camera check to reversible adjustment and re-check.
OpenBikeFit
Free, private bike fitting: evidence-led calculators, on-device camera measurement and a repeatable adjustment loop.
Educational guidance, not a diagnosis or a substitute for a qualified fitter. Stop when symptoms persist or worsen.